Peri-Implantitis and Soft Tissue Dehiscence in a Turkish Population: Risk Indicators, Diagnostic Parameters and Biomarkers Discovery.

Aim
To assess (i) the risk indicators of peri-implantitis and peri-implant soft-tissue dehiscence (PISTD), and (ii) the accuracy of clinical parameters and peri-implant crevicular fluid (PICF) immunological markers in diagnosing peri-implantitis, within a Turkish university population.
Methods
A total of 324 implants in 112 patients were included. The outcomes for the risk indicators analysis were the presence of peri-implantitis and PISTD, with peri-implantitis also serving as the reference standard for the diagnostic accuracy analysis. Several potential risk indicators-including demographic, medical, and dental history, clinical and radiographic parameters, and dental chart data-were assessed using multilevel logistic regressions. The diagnostic performance of clinical parameters and PICF immunological markers was evaluated using logistic regressions and reporting sensitivity, specificity, positive/negative predictive values, and area under the curve (AUC) values.
Results
In the final multilevel logistic regression, the following indicators were associated with peri-implantitis: stage III-IV periodontitis (OR = 5.67), irregular maintenance (SPIC) compliance (OR = 7.71), history of implant loss (OR = 14.44), implant system, absence of keratinized mucosa (KM) (OR = 8.41), and clinical attachment loss in adjacent teeth (OR = 3.75). Risk indicators for PISTD included: mandibular location (OR = 0.22), implant system, absence of KM (OR = 5.95), and mucosal thickness < 2 mm (OR = 197.01). Peri-implant bleeding on probing (BoP) at 2 or more sites had the highest sensitivity for peri-implantitis (98.0%), while the highest specificity was observed for BoP severity (modified Bleeding Index 2-3 = 96.4%). The highest AUC was found for peri-implant probing pocket depth (PPD) ≥ 6 mm (0.88). Among PICF immunological markers, IL-2 and IL-10 exhibited the highest sensitivity (100.0%), while TNF-α had the highest specificity (92.9%). IL-8 and TNF-α had the highest AUC values (0.80).
Conclusion
In this Turkish university cohort, several risk indicators were identified for peri-implantitis and PISTD. Among clinical parameters, only PPD ≥ 6 mm demonstrated strong diagnostic accuracy for peri-implantitis. Several PICF immunological markers, particularly IL-8 and TNF-α, showed promising diagnostic potential.